The present invention relates to the making of instant images in general, and more particularly to improvements in a method and apparatus for making instant images in accordance with the diffusion transfer technique. Still more particularly, the invention relates to a method of manipulating various types of film units, to an apparatus which can be used for the practice of such method, and to improvements in containers or cassettes for supplies of film units.
U.S. Pat. No. 2,458,186 granted Jan. 4, 1949 to Messina et al. discloses a photographic apparatus which uses film units of the type wherein a negative sheet which is to be exposed to light and a positive sheet which is to bear the image overlap each other during transport through the nip of pressure applying rolls which cause a pod for a supply of fluid processing agent to burst open and to permit the processing agent to spread between the positive and negative sheets. The two sheets are separated from each other upon completion of the developing step. The developing step is completed within a certain interval of time, e.g., approximately one minute. When the image-bearing positive sheet is separated from the negative sheet, from the pod and from a customary trap for the surplus of processing agent, the user of the photographic apparatus is often confronted with the problem of disposing with the remnant of the film unit. Such problem is aggravated by the fact that the processing agent contains certain aggressive chemicals which coat a portion of the remnant of the film unit, namely, that portion which includes the exposed negative sheet, the pod and the trap. In many situations, the disposal of such remnant upon completion of the developing step is quite problematic, e.g., when the user of the apparatus is not permitted to drop the remnant on the ground or the user cannot avail himself or herself of a waste basket or another suitable receptacle for disposable commodities or substances.
A film unit of the type used in the apparatus of Messina et al. includes an image bearing positive sheet as well as a remnant consisting of an exposed sheet, an evacuated pod, a trap for surplus processing agent as well as a frame for the image-bearing component. The photographic apparatus of Messina et al. employs a drum or roll which collects the remnants of successive film units. The drum can be removed from the housing of the photographic apparatus and can be discarded together with the convoluted waste material. Such apparatus failed to gain widespread acceptance for numerous reasons. Thus, the patentees draw the positive and negative sheets from discrete reels. This limits the number of image sizes which can be obtained in such apparatus. Furthermore, the drum for waste material and the remnants which are convoluted thereon occupy a substantial amount of space so that the patented apparatus is rather bulky. Still further, the user must carry along a supply of spare drums in addition to supplies of reels with positive and negative sheets. All this contributes to complexity and cost of the patented apparatus and involves a substantial amount of work upon completion of a certain number of exposures.
U.S. Pat. No. 3,767,404 granted Oct. 23, 1973 to Harvey discloses a modified photographic apparatus for use with film units, each of which contains a relatively stiff sheet which is called a card and constitutes a carrier for the pod and for the trap. The card further supports a sheet of negative material and the image-receiving sheet, and such sheets are readily separable from the carrier. The patented photographic apparatus embodies means for separating the two sheets from the carrier or card immediately after passage through the nip of the pressure applying rolls. The carrier or card is flexed and introduced into an empty portion of the interior of a container for film units. A drawback of the patented apparatus is that it must employ the just discussed complex and highly expensive film units wherein the negative and image bearing sheets are separably attached to a card-like carrier which latter further supports a pod and a trap for the surplus of fluid processing agent.
It is also known to employ so-called instant-image cameras which utilize film units of the type known as monopanel film units. One of the two sheets in such film units transmits light so that the exposure can be made while the two sheets (namely, the light-transmitting sheet and the other sheet) overlap each other in the interior of the camera housing during exposure of the respective unit to scene light. In such monopanel film units, the pod and the trap are integrated into the unit, and the developing step need not be followed by a separating step because the entire film unit constitutes a photographic print. The reproduced image is observed through the light-transmitting sheet of the film unit, and the pod as well as the trap remain in the ultimate product. A drawback of such ultimate products is that they are rather stiff and relatively thick, especially in the region of the trap for the surplus processing agent. Moreover, the presence of a surplus of fluid processing agent in the ultimate product is likely to create problems, especially as concerns the quality of the image and/or the likelihood of contamination of objects which come in contact with the final product.